Pneumonia Pneumonia is an infection in one or both lungs. The infection may be caused by fungi, bacteria, or viruses. Pneumonia causes inflammation in your lung’s air sacs, also referred to as alveoli. The alveoli fill with fluid or pus, making it difficult to breathe. Symptoms of pneumonia can range from mild to life threatening.
Mycoplasma pneumonia may occur in association with swelling of the lymph nodes in the neck, joint pain, or an middle ear infection. Viral pneumonia presents more commonly with wheezing than does bacterial pneumonia